The waitid support is missing (as advertised by the miss of the WEXITED, WSTOPPED, WCONTINUED, and WNOWAIT macros).
Fixed in master: commit f6abd970284a06380cd9d905f43da104bd49fc95 (HEAD -> master) Author: Samuel Thibault <samuel.thibault@ens-lyon.org> Date: Mon Dec 28 23:37:04 2020 +0100 hurd: Add WSTOPPED/WCONTINUED/WEXITED/WNOWAIT support [BZ #23091] The new __proc_waitid RPC now expects WEXITED to be passed, allowing to properly implement waitid, and thus define the missing W* macros (according to FreeBSD values).